The goal of this Core is to provide DNA, RNA, protein and tissue samples, as well as lymphoblasts and hemangioma derived endothelial cells for analysis related to all three projects of this Program Project. In addition, the Core collects clinical information and pedigree data pertinent to the samples. This data is essential not only for the genetic approaches (Projects 1 and 3), but also when analysing tissues or cell lines for differential expression, somatic mutations or altered behaviour in cell culture in vascular anomaly subtypes (Projects 1, 2 and 3). The sample collection will also ultimately serve for fast and efficient screening of newly identified candidate genes in a well-characterized sample set. The work of Core C is largely based on the extensive collaborative work and expertise of Dr J.B. Mulliken, Vascular Anomalies Center, Boston and Dr L.M. Boon, Vascular Anomalies Center, Brussels. This collaboration has led to numerous clinical publications describing novel diagnostic measures, prevalence and treatment of vascular anomalies. In addition, in collaboration with Drs Vikkula and Olsen, genetic background has been elucidated for certain forms. On this basis, we have already collected 115 families, 291 blood samples, 317 tissue samples, and established 125 cell lines. This unique collection of well-characterized samples will be enlarged continuously throughout the Program Project. This allows access of all three Projects of this Program Project to sufficient numbers of samples that are essential for achieving the Aims.